The Department of Medicinal Chemistry and Pharmacognosy at Purdue University requests funds for the acquisition of a Varian Gemini-300 NMR spectrometer system, with broad-band probes and electronics, variable-temperature capability, and an Ethernet link to a SUN Microsystems SPARC workstation (also requested). The Gemini-300 will replace older and less capable 200 MHz instruments and will allow multinuclear one-dimensional survey spectra (e.g., 1H, 13C, 19F, and 31p) and various two-dimensional experiments to be run routinely, in a "walk-on" mode. The SPARC workstation will also be networked to an existing Varian VXR-500, thus allowing data processing and hard copy production to be accomplished off-line, and maximizing the use of both spectrometers for the acquisition of spectral data. The Major Users' needs for multinuclear observation, variable temperature capability, and an off-line workstation are documented, and a justification for the purchase of a computer-switchable, four-nucleus VT probe is presented. The Major User group comprises 12 faculty members from the Department of Medicinal Chemistry and Pharmacognosy. Dr. Schwab's project concerns the structures and catalytic mechanisms of several bacterial enzymes, and the synthesis of isotopically labeled enzyme substrates and inactivators. Dr. Bergstrom will synthesize and characterize modified oligonucleotides and study their interactions with nucleic acids. Dr. Byrn will synthesize and characterize oligonucleotides tethered to acridines and anthracyclines as potential antiviral agents. Dr. Chang's research concerns the discovery of novel antitumor agents from higher plants, guided by ii variety of mechanism-based bioassays. Dr. Cushman describes the synthesis of a wide range of potential antiviral, antitumor, and antibacterial agents. Dr. Davisson will study enzyme mechanisms in the bacterial pathway for histidine biosynthesis. Dr. Green will synthesize radiopharmaceuticals labeled with metal radionuclides, for use in positron emission tomography (PET). Dr. Loudon is developing new chemical techniques for the identification of peptide hormones in crude biological preparations. Dr. McLaughlin's research centers about the isolation and characterization of novel bioactive principles from higher plants, using several simple and inexpensive, yet effective, bioassays. Dr. Nichols conducts structure-activity studies of dopamine and serotonin agonists and antagonists. Dr. Pidgeon is synthesizing and using NMR spectroscopy to study the structures and dynamics of phospholipids that are covalently linked to silica (immobilized artificial membranes). Dr. Post will use NMR relaxation measurements to probe the active site metal ion environment of phosphoglucomutase. The need for an updated "walk-on" NMR spectrometer is highlighted by the recent growth of the Department's faculty (including five new faculty members over the past two years) as well as the strongly chemical nature of the research being conducted in the Department.